1. Technical Field.
The present invention relates to the conversion of liquid fuel to gaseous form and particularly to a method and apparatus for producing a flow of combustible gaseous mixture of fuel and air by centrifugal action for use in a combustion apparatus, particularly in an internal combustion engine.
2. Background Art.
Nonuniform mixing of fuel and air and fuel condensation in the intake passages of internal combustion engines are known to increase fuel consumption and pollution. Conventional venturi carburetors deliver liquid fuel in a finely-divided spray, part of which tends to condense upon cold intake passage walls. To assure that a combustible mixture will reach the cylinders, the carburetor must be adjusted to give a rich mixture during engine warm up. In addition, the delivery of fuel in the form of droplets makes it difficult to achieve completely uniform mixing with the intake air flowing through the carburetor.
Various proposals have been made for producing a homogeneous mixture of vaporized fuel and air by rotational mixing, sometimes in combination with heating or exposure to a gasifying catalyst, as in U.S. Pat. Nos. 2,351,072 of H. H. Schmidt, 4,053,013 of P. Guba, 4,264,539 of R. E. Berg, and 3,946,717 of England.
Schmidt introduces a fuel/air mixture from a carburetor or other source into a stationary chamber containing a disc-like rotor having vanes extending from the center to the circumference on both sides of the disc. The rotor disc subdivides the chamber into two halves, and the mixture is introduced into each half through a respective opening spaced from the axis of rotation approximately two-thirds of the radius of the chamber. The portions of the mixture entering these openings come into engagement with the rotor vanes and are given a violent centrifugal whirling motion, causing them to be thrown outwardly toward the periphery of the partitioning disc and into contact with the side walls of the chamber. The whirled mixture then leaves the chamber through a tangential outlet passage.
Guba imparts a centrifugal force to a fuel/air mixture supplied from a carburetor by passing the mixture through a rotor comprising a plurality of tubular members arranged in a circle and extending in directions that are slightly skewed from parallel to the axis of rotation. The tubular members are heated by a second fluid passing in contact with the outside surfaces of the tubes, so that the fuel/air mixture is pumped out of the tubular members centrifugally in a preheated condition.
Berg supplies fuel and air through separate coaxial tubes to the center of a squirrel cage type of centrifugal fan that rotates in a stationary housing which has a single off-center outlet. England discloses a fuel vaporizer having a flow-driven spinning bowl suspended from a conical sieve fixed in an inlet passage downstream from a carburetor. According to England, liquid fuel droplets impact the bottom of the bowl, and the captured liquid is centrifugally forced outward by the spin of the bowl. The bowl sides are described as directing the liquid flow to the backside of the sieve. Since the bowl rim is at the maximum diameter of the bowl, however, it would be inevitable that much of any captured liquid fuel would be sprayed outward from the rim of the spinning bowl into contact with the wall of the intake passage.